XML 78 R63.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value of Financial Instruments (Textual) (Details) - USD ($) $ in Millions | 1 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Mar. 31, 2020 | Jun. 30, 2018 | Jun. 26, 2018
Third Party [Member] |  |  |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |  |  |
Note receivable |  | $ 3.4 |
Mortgage loans, interest rate for remainder of 2018 |  | 7.00% |
Mortgage loans, interest rate after 2018 until maturity date in March of 2020 |  | 8.00% |
Mortgage loans, maturity date |  | 2020-03 |
Third Party [Member] | Scenario Forecast [Member] |  |  |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |  |  |
Amount expected to be received from note receivable | $ 3.1 |  |
Brandywine 1919 Ventures [Member] |  |  |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |  |  |
Mortgage loan |  |  | $ 44.4
Equity method investment, ownership percentage |  |  | 50.00%
Brandywine 1919 Ventures [Member] | Other Assets [Member] |  |  |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |  |  |
Note receivable |  |  | $ 44.4

X
- Definition Mortgage loans interest rate for remainder of fiscal year. + References No definition available. + Details
Name: | bdn_MortgageLoansInterestRateForRemainderOfFiscalYear
Namespace Prefix: | bdn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Mortgage loans interest rate for year two and thereafter. + References No definition available. + Details
Name: | bdn_MortgageLoansInterestRateForYearTwoAndThereafter
Namespace Prefix: | bdn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Mortgage loans maturity date, month and year. + References No definition available. + Details
Name: | bdn_MortgageLoansMaturityDateMonthAndYear
Namespace Prefix: | bdn_
Data Type: | xbrli:gYearMonthItemType
Balance Type: | na
Period Type: | duration

X
- Definition Notes receivable final payment. + References No definition available. + Details
Name: | bdn_NotesReceivableFinalPayment
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29(Column G)) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 + Details
Name: | us-gaap_MortgageLoansOnRealEstate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.10(3)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_CounterpartyNameAxis=bdn_ThirdPartyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bdn_BrandywineNineteenNineteenVenturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |